基于空间外差的三叶草拉曼特征光谱测量实验研究

doi:10.3964/j.issn.1000-0593(2020)07-2110-06

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Abstract The spatial heterodyne spectroscopy technology has been widely used in the detection of weak spectral signals such as interstellar dark matter and atmospheric trace gas components by virtue of its ultra-high spectral resolution, high through put, transient detection, and no moving parts. In order to study the feasibility of real-time Raman spectroscopy (RS) based on spatial heterodyne spectroscopy, and the integratedspatial heterodyne spectroscopy system HEP-765-S is used as the Raman characteristic spectrum detector. Firstly, Gaussview6.0 was used to construct the molecular structure of the main pigments in clover: chlorophyll a, chlorophyll b, α-carotene and β-carotene. Then Gaussian16 was used to obtain the optimized simulated RS, analyze the band range of the strongest Raman spectrum peaks of the four pigments, and determine the strong signal characteristic bands of the four components were 1 537~1 800 cm^-1. According to the theoretical relationship between the excitation light source and the Raman displacement, combined with the detection band range of the detection system of 759~769 nm. It is calculated that the laser with the wavelength of 680 nm can be used as the light source to stimulate the Raman signal, which can ensure that the Raman signals with the strong characteristic of four pigments fall within the detection range, and avoid the influence of Rayleigh scattering light and fluorescence interference of the light source. Finally, a laser with a central wavelength of 680.28 nm and space heterodyne spectrum system HEP-765-S were purchased to conduct the direct detection experiment of clover strong peak Raman signal. The results show that the system can directly measure the RS of clover, but the measured Raman signal strength is weak, which is mainly caused by two reasons: one is that the peak power of the laser used is relatively small. Second, the space heterodyne spectrum system HEP-765-S is an integrated design instrument. The software and hardware system and parameters cannot be adjusted after curing, and the maximum integral time of instrument data collection is 832 ms. The acquisition signal is weak due to the insufficient power of the light source and the small instrument integral. Compared with the simulated spectrum, the measured spectrum in the detection band of the spatial heterodyne system is basically consistent with the envelope superimposed by Raman signals of four main pigments in clover leaves. The main peak ends with time are in line with the good, the measured spectra and simulation spectrum has a good consistency, using the spatial heterodyne system for material Raman signal is quick, direct detection is feasible.

Key words：Spatial heterodyne detection system; Raman spectroscopy; Gaussian calculation; Clover

Received: 2019-06-07 Accepted: 2019-10-16

ZTFLH:

O433.4

Corresponding Authors: LI Shu E-mail: lishu_owen@sina.com

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https://www.gpxygpfx.com/EN/10.3964/j.issn.1000-0593(2020)07-2110-06 OR https://www.gpxygpfx.com/EN/Y2020/V40/I07/2110